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8 Cards in this Set
- Front
- Back
1. What is insulin?
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- Main hormone controlling intermediary metabolism
- lowers blood glucose - This coupled with reduced insulin resistance --> diabetes mellitus - acts on liver, muscle, fat - overall effect: conserve fuel by facilitating the uptake and storage of glucose, amino acids, and fats after a meal. |
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2. Where is insulin secreted from?
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The pancreas, the B-cells in the islets of Langerhans
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3. Which factors regulate or influence the secretion of insulin?
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- blood glucose concentration
- gastrointestinal hormones secrete insulin (gastrin, secretin, GIP, GLP, GLP1, cholecystokinin) - other stimuli that release insulin: amino acids (esp. leucine and arginine), fatty acids, parasympathetic nervous system, drugs that act on sulfonylurea receptors - inhibited by the sympathetic nervous system - adrenaline increases blood glucose by inhibiting insulin secretion and other ways - other inhibitors are several peptides like somatostatin, galanin, amylin |
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4. What are the effects of insulin on carbohydrate metabolism?
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- In liver, insulin inhibits glycogen breakdown and synthesis of glucose from non-carb sources.
- While stimulating glycogen synthesis - overall effect is to increase hepatic glycogen stores - in muscle, slow uptake of glucose is the rate limiting step for carb metabolism - thus, insulin increases facilitated uptake of glucose by the transporter Glut-4 (And in adipose tissue) - insulin also stimulates glycogen synthesis and glycolysis |
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5. What are the effects of insulin on fat metabolism?
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- Insulin increases fatty acids and trigylceride synthesis in: adipose tissue and the liver, while simultaneously inhibiting lipolysis
- also inhibits adrenaline's, glucagon's and growth hormone's lipolytic actions on adenylate cyclase |
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6. What are the effects of insulin on protein metabolism?
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stimulates uptake of amino acids into muscle
increases protein synthesis while decreasing protein catabolism and oxidation of amino acids in the liver |
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7. Are there any additional effects of insulin?
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other metabolic effects of insulin:
transporting K+, Ca2+, nucleosides, inorganic phosphates into the cells insulin has a rapid effects on metabolism, exerted via an altered activity of enzymes and transported proteins also has longer term actions via altered enzyme synthesis - cell proliferation in somatic and visceral growth |
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8. Is insulin a catabolic or anabolic hormone?
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Anabolic
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